Relationship between femoral anteversion and findings in hips with femoroacetabular impingement

A New Clinical Examination Algorithm to Prescribe Conservative Treatment in People with Hip-Related Pain

Hip-related pain is a common issue in active adults affecting their quality of life, mobility, and overall function, and it can lead to persistent disability. However, diagnosing hip-related pain is challenging due to the many potential sources and causes, including intra-articular and extra-articular pathology, and referred pain from other areas (lumbar or groin related pain). To address this, there is a need for a clinical algorithm based on the best available evidence and expert consensus. This algorithm could guide healthcare professionals in assessing and managing patients with hip-related pain, during the diagnosis, test selection, intervention, monitoring, and promoting collaboration among various healthcare providers. This clinical algorithm for hip-related pain is a comprehensive, flexible, adaptable to different settings, and regularly updated to incorporate new research findings. This literature review aims to establish a clinical algorithm specifically for prescribing exercise treatment to patients with hip-related pain, addressing their individual needs and enhancing their overall care.

Mechanical effect of changed femoral neck ante-version angles on the stability of an intertrochanteric fracture fixed with PFNA: A finite element analysis

Objective

Change of femoral neck ante-version angle postoperatively due to inadequate reduction could result in unsatisfying treatment outcome of intertrochanteric fracture. However, the influence of increased or decreased femoral neck ante-version on the biomechanical stability of the bone-implant complex has rarely been studied.

Methods

A finite element model of a complete normal human femur with normal femoral neck ante-version as 13° was established accurately by scanning a 64 year old female femur. The models of 31-A1.1 intertrochanteric fractures with different femoral neck ante-version angles of 3°, 5.5°, 8°, 10.5°, 13°, 15.5°, 18°, 20.5°, 23° were created. They were assembled with a proximal femoral nail anti-rotation (PFNA) device. The biomechanical differences with varying femoral neck ante-version angles were compared using finite element analysis method.

Results

As the femoral neck ante-version angle gradually increased from 13° to 23°with a gradient of 2.5°, the peak von Mises stress was gradually increased from 137.82 MPa to 276.02 MPa. Similarly, the peak von Mises stress was gradually increased from 137.82 MPa to 360.12 MPa with the femoral neck ante-version angle decreased from 13° to 3°. When decreased ante-version angle of 7.5° and increased ante-version angle of 10° will exceed the yield strength of femoral (240.32 MPa), the risk of femoral fracture will increase significantly. The maximum displacement of the femur was significantly reduced for increased ante-version models than for decreased ante-version models, whether the changes of ante-version angles were 2.5°, 5°, 7.5° or 10°. The maximum stress of PFNA was found in the intersection of main nail and helical blade, and became greater gradually as the ante-version angle increased or decreased with a gradient of 2.5°. The maximum stress of PFNA was presented in the model 5.5° with the maximum stress of 724.42 MPa (near to the yield strength of titanium alloy of 700-1000 MPa), producing the breakage risk of PFNA. The maximum displacement of the PFNA was significantly reduced for increased ante-version models than for decreased ante-version models, whether the changes of ante-version angles were 2.5°, 5°, 7.5° or 10°.

Conclusion

Based on the results of present study, it was demonstrated that the anatomical reduction of femoral neck ante-version was vital to secure the optimal stability. Abnormal femoral ante-version could increase the potential risk of failure for intertrochanteric fracture after PFNA. The stability of increased femoral ante-version (less than 10°) was superior to the stability of decreased ante-version (less than 5°) for the cases of difficulty to acquire anatomical reduction. The clinical implication of the finding was that increased femoral neck ante-version had an advantage of mechanical stability towards the decreased femoral neck ante-version for the cases of comminuted intertrochanteric fracture and failure of anatomical reduction.

Effect of different constraining boundary conditions on simulated femoral stresses and strains during gait

Finite element analysis (FEA) is commonly used in orthopaedic research to estimate localised tissue stresses and strains. A variety of boundary conditions have been proposed for isolated femur analysis, but it remains unclear how these assumed constraints influence FEA predictions of bone biomechanics. This study compared the femoral head deflection (FHD), stresses, and strains elicited under four commonly used boundary conditions (fixed knee, mid-shaft constraint, springs, and isostatic methods) and benchmarked these mechanics against the gold standard inertia relief method for normal and pathological femurs (extreme anteversion and retroversion, coxa vara, and coxa valga). Simulations were performed for the stance phase of walking with the applied femoral loading determined from patient-specific neuromusculoskeletal models. Due to unrealistic biomechanics observed for the commonly used boundary conditions, we propose a novel biomechanical constraint method to generate physiological femur biomechanics. The biomechanical method yielded FHD (< 1 mm), strains (approaching 1000 µε), and stresses (< 60 MPa), which were consistent with physiological observations and similar to predictions from the inertia relief method (average coefficient of determination = 0.97, average normalized root mean square error = 0.17). Our results highlight the superior performance of the biomechanical method compared to current methods of constraint for  both healthy and pathological femurs.

What Is the Influence of Femoral Version on Size, Tear Location, and Tear Pattern of the Acetabular Labrum in Patients With FAI?

BACKGROUND

Femoral version deformities have recently been identified as a major contributor to femoroacetabular impingement (FAI). An in-depth understanding of the specific labral damage patterns caused by femoral version deformities may help to understand the underlying pathomorphologies in symptomatic patients and select the appropriate surgical treatment.

QUESTIONS/PURPOSES

We asked: (1) Is there a correlation between femoral version and the mean cross-sectional area of the acetabular labrum? (2) Is there a difference in the location of lesions of the acetabular labrum between hips with increased femoral version and hips with decreased femoral version? (3) Is there a difference in the pattern of lesions of the acetabular labrum between hips with increased femoral version and hips with decreased femoral version?

METHODS

This was a retrospective, comparative study. Between November 2009 and September 2016, we evaluated 640 hips with FAI. We considered patients with complete diagnostic imaging including magnetic resonance arthrography (MRA) of the affected hip with radial slices of the proximal femur and axial imaging of the distal femoral condyles (allowing for calculation of femoral version) as eligible. Based on that, 97% (620 of 640 hips) were eligible; a further 77% (491 of 640 hips) were excluded because they had either normal femoral version (384 hips), incomplete imaging (20 hips), a lateral center-edge angle < 22° (43 hips) or > 39° (16 hips), age > 50 years (8 hips), or a history of pediatric hip disease (20 hips), leaving 20% (129 of 640 hips) of patients with a mean age of 27 ± 9 years for analysis, and 61% (79 of 129 hips) were female. Patients were assigned to either the increased (> 30°) or decreased (< 5°) femoral version group. The labral cross-sectional area was measured on radial MR images in all patients. The location-dependent labral cross-sectional area, presence of labral tears, and labral tear patterns were assessed using the acetabular clockface system and compared among groups.

RESULTS

In hips with increased femoral version, the labrum was normal in size (21 ± 6 mm2 [95% confidence interval 20 to 23 mm2]), whereas hips with decreased femoral version showed labral hypotrophy (14 ± 4 mm2 [95% CI 13 to 15 mm2]; p < 0.01). In hips with increased femoral version, labral tears were located more anteriorly (median 1:30 versus 12:00; p < 0.01). Hips with increased femoral version exhibited damage of the anterior labrum with more intrasubstance tears anterosuperiorly (17% [222 of 1322] versus 9% [93 of 1084]; p < 0.01) and partial tears anteroinferiorly (22% [36 of 165] versus 6% [8 of 126]; p < 0.01). Hips with decreased femoral version showed superior labral damage consisting primarily of partial labral tears.

CONCLUSION

In the evaluation of patients with FAI, the term "labral tear" is not accurate enough to describe labral pathology. Based on high-quality radial MR images, surgeons should always evaluate the combination of labral tear location and labral tear pattern, because these may provide insight into associated femoral version abnormalities, which can inform appropriate surgical treatment. Future studies should examine symptomatic patients with normal femoral version, as well as an asymptomatic control group, to describe the effect of femoral version on labral morphology across the entire spectrum of pathomorphologies.

LEVEL OF EVIDENCE

Level III, prognostic study.

Discrepancies in MR- and CT-Based Femoral Version Measurements Despite Strong Correlations

PURPOSE

To determine the correlation and classification consistency of femoral version measurements between magnetic resonance (MR) and computed tomography (CT) using 4 commonly used measurement methods.

METHODS

A retrospective study was performed on patients with femoroacetabular impingement (FAI) who received preoperative CT and MR imaging assessment of the surgical hip and ipsilateral distal femur. Femoral version was measured using the Murphy method, the oblique method, the Reikerås method, and the Lee method. Intra- and inter-rater agreements were calculated. Linear regression and Bland-Altman analysis were performed for measurements using different imaging modalities and measurement methods. Femoral version measurements within the lower quartile, the middle 2 quartiles, and the upper quartile were classified into different groups based on their percentile within the sample population. Classification consistency rates between modalities and methods were calculated and compared.

RESULTS

Fifty-three patients (39.4 ± 9.1 years; 32 female) were included for analysis. Intra- and inter-rater reliability were high for all modalities and methods (intrarater intraclass correlation coefficient [ICC] range, 0.963-0.993; inter-rater ICC range, 0.871-0.960). MR- and CT-based femoral version measurements showed strong correlations for all methods, with the Lee method demonstrating the strongest association (r = 0.904), while the oblique method exhibited the lowest correlation (r = 0.684) (all P < .001). MR-based measurements were smaller than CT-based measurements, with mean differences ranging from 4.5° to 10.3°. Classification consistency between MR and CT ranged from 51% to 74%, whereas the consistency between different measurement methods ranged from 68% to 85%.

CONCLUSIONS

While strong correlations were observed between MR- and CT-based femoral version measurements, MR-based measurements were significantly smaller than their CT counterparts. Classification consistency between the modalities was moderate to high. Measurements between different methods showed strong correlations with high consistency rates.

LEVEL OF EVIDENCE

Level III, retrospective case series.

Non-Operative Rehabilitation Principles for Use in Individuals with Acetabular Dysplasia: A North American Based Delphi Study

Background

Acetabular dysplasia (AD) is defined as a structurally deficient acetabulum and is a well-recognized cause of hip pain in young adults. While treatment of severe AD with a periacetabular osteotomy has demonstrated good long-term outcomes, a trial of non-operative management is often recommended in this population. This may be especially true in patients with milder deformities. Currently, there is a paucity of research pertaining to non-operative management of individuals with AD.

Purpose

To present expert-driven non-operative rehabilitation guidelines for use in individuals with AD.

Study Design

Delphi study.

Methods

A panel of 15 physiotherapists from North America who were identified as experts in non-operative rehabilitation of individuals with AD by a high-volume hip preservation surgeon participated in this Delphi study. Panelists were presented with 16 questions regarding evaluation and treatment principles of individuals with AD. A three-step Delphi method was utilized to establish consensus on non-operative rehabilitation principles for individuals presenting with AD.

Results

Total (100%) participation was achieved for all three survey rounds. Consensus, defined a piori as > 75%, was reached for 16/16 questions regarding evaluation principles, activity modifications, appropriate therapeutic exercise progression, return to activity/sport criteria, and indications for physician referral.

Conclusion

This North American based Delphi study presents expert-based consensus on non-operative rehabilitation principles for use in individuals with AD. Establishing guidelines for non-operative management in this population will help reduce practice variation and is the first step in stratifying individuals who would benefit from non-operative management. Future research should focus on patient-reported outcomes and rate of subsequent surgical intervention to determine the success of the guidelines reported in this study.

Level of Evidence

Level V.

Combined femoral and acetabular version and synovitis are associated with dGEMRIC scores in people with femoroacetabular impingement (FAI) syndrome

This study sought to explore, in people with symptoms, signs and imaging findings of femoroacetabular impingement (FAI syndrome): (1) whether more severe labral damage, synovitis, bone marrow lesions, or subchondral cysts assessed on magnetic resonance imaging (MRI) were associated with poorer cartilage health, and (2) whether abnormal femoral, acetabular, and/or combined femoral and acetabular versions were associated with poorer cartilage health. This cross-sectional study used baseline data from the 50 participants with FAI syndrome in the Australian FASHIoN trial (ACTRN12615001177549) with available dGEMRIC scans. Cartilage health was measured using delayed gadolinium-enhanced MRI of cartilage (dGEMRIC) score sampled at the chondrolabral junction on three midsagittal slices, at one acetabular and one femoral head region of interest on each slice, and MRI features were assessed using the Hip Osteoarthritis MRI Score. Analyses were adjusted for alpha angle and body mass index, which are known to affect dGEMRIC score. Linear regression assessed the relationship with the dGEMRIC score of (i) selected MRI features, and (ii) femoral, acetabular, and combined femoral and acetabular versions. Hips with more severe synovitis had worse dGEMRIC scores (partial η2  = 0.167, p = 0.020), whereas other MRI features were not associated. A lower combined femoral and acetabular version was associated with a better dGEMRIC score (partial η2  = 0.164, p = 0.021), whereas isolated measures of femoral and acetabular version were not associated. In conclusion, worse synovitis was associated with poorer cartilage health, suggesting synovium and cartilage may be linked to the pathogenesis of FAI syndrome. A lower combined femoral and acetabular version appears to be protective of cartilage health at the chondrolabral junction.

Excessive Femoral Anteversion Leading to Symptomatic Posterior Femoroacetabular Impingement, Cam Deformity of the Posterior Femoral Head-Neck Junction, and Anterior Hip Instability in a Dancer: A Case Report

CASE

An adolescent female dancer with excessive femoral anteversion presented with posterior and anterior hip pain aggravated by poses that required extension and external rotation. Imaging revealed an atypical cam deformity of the posterior head-neck junction. During surgery, the posterior head-neck junction was observed to impinge on the posterior acetabulum with anterior subluxation of the hip. After a derotational femoral osteotomy, the patient experienced resolution of her symptoms.

CONCLUSION

Excessive femoral anteversion can lead to reactive cam deformity, posterior intra-articular impingement, and anterior hip instability in patients who require repetitive hip extension and external rotation, such as ballet dancers.

Femoral and acetabular features explain acetabular contact pressure sensitivity to hip internal rotation in persons with cam morphology: A finite element analysis

BACKGROUND

Femoroacetabular impingement is characterized by premature contact between the proximal femur and acetabulum. The loss of femoral head-neck concavity associated with cam morphology leads to mechanical impingement during hip flexion and internal rotation. Other femoral and acetabular features have been linked with mechanical impingement but have not been comprehensively investigated. This study sought to determine which bony features are most influential in contributing to mechanical impingement in persons with a cam morphology.

METHODS

Twenty individuals (10 female, 10 male) with a cam morphology participated. Finite element analyses incorporating subject-specific bony geometry derived from computed tomography scans were used to determine which femoral (alpha angle and femoral neck-shaft angle) and acetabular (anteversion angle, inclination angle, depth, and lateral center-edge angle) features accentuate acetabular contact pressure with increasing degrees of hip internal rotation with the hip flexed to 90°. To determine the best predictors of acetabular contact pressure sensitivity to internal rotation, all morphological variables were included in a stepwise regression with the final model subjected to a bootstrapping procedure.

FINDINGS

The stepwise regression revealed that femoral neck-shaft angle, acetabular anteversion angle, acetabular inclination angle, and acetabular depth were the best combination of variables to predict contact pressure sensitivity to internal rotation, explaining 55% of the variance. Results of the bootstrap analysis revealed that a median value of 65% [37%, 89%] variance in sensitivity could be explained by these morphological variables.

INTERPRETATION

Mechanical impingement and the concomitant acetabular contact pressure are modulated by multiple femoral and acetabular features in persons with a cam morphology.

Change of Femoral Anteversion Angle in Children With Intoeing Gait Measured by Three-Dimensional Computed Tomography Reconstruction: 3-Year Follow-Up Study

OBJECTIVE

To investigate long-term changes in femoral anteversion angle (FAA) in children with intoeing gait and to identify factors that affect FAA changes.

METHODS

We retrospectively analyzed three-dimensional computed tomography data from 2006 to 2022 of children with intoeing gait with ≥3 years of follow-up without active treatment. The study examined the mean changes in FAA, the effects of sex, age, and initial FAA on FAA change, and mean FAAs by age. Changes in FAA severity up to eight years of age were also observed and analyzed by sex.

RESULTS

A total of 126 lower limbs of 63 children (30 males, 33 females) with intoeing gait were included, with a mean age of 5.11±1.05 years and a mean follow-up period of 43.59±7.74 months. The initial FAA was 41.42°±8.29° and the follow-up FAA was 33.25°±9.19°, indicating a significant decrease (p<0.001). Significant correlations were observed between age and changes in FAA, as well as between initial FAA and changes in FAA (r=0.248, p=0.005; r=-0.333, p<0.001). At age 8 years, only 22 limbs were classified as having mild FAA severity.

CONCLUSION

During the follow-up period, children with intoeing gait had a significant decreased in FAA. No significant difference in FAA change was found between sex, but younger children and those with greater initial FAA were more likely to have decreased FAA. However, most children retained moderate to severe severity of increased FAA. Further studies are required to validate these findings.

Which hip morphology measures and patient factors are associated with age of onset and symptom severity in femoroacetabular impingement syndrome?

BACKGROUND

Bony morphology is central to the pathomechanism of femoroacetabular impingement syndrome (FAIS), however isolated radiographic measures poorly predict symptom onset and severity. More comprehensive morphology measurement considered together with patient factors may better predict symptom presentation. This study aimed to determine the morphological parameter(s) and patient factor(s) associated with symptom age of onset and severity in FAIS.

METHODS

99 participants (age 32.9 ± 10.5 years; body mass index (BMI 24.3 ± 3.1 kg/m²; 42% females) diagnosed with FAIS received standardised plain radiographs and magnetic resonance scans. Alpha angle in four radial planes (superior to anterior), acetabular version (AV), femoral torsion, lateral centre-edge, anterior centre-edge (ACEA) and femoral neck-shaft angles were measured. Age of symptom onset (age at presentation minus duration of symptoms), international Hip Outcome Tool-33 (iHOT-33) and modified UCLA activity scores were recorded. Backward stepwise regression assessed morphological parameters and patient factors (age, sex, BMI, symptom duration, annual income, private/public healthcare system accessed) to determine variables independently associated with onset age and iHOT-33 score.

RESULTS

Earlier symptom onset was associated with larger superoanterior alpha angle (p = 0.007), smaller AV (p = 0.023), lower BMI (p = 0.010) and public healthcare system access (p = 0.041) (r² = 0.320). Worse iHOT-33 score was associated with smaller ACEA (p = 0.034), female sex (p = 0.040), worse modified UCLA activity score (p = 0.010) and public healthcare system access (p < 0.001) (r² = 0.340).

CONCLUSIONS

Age of symptom onset was chiefly predicted by femoral and acetabular bony morphology measures, whereas symptom severity predominantly by patient factors. Factors measured explained a small amount of variance in the data; additional unmeasured factors may be more influential.

Correlation of femoral version measurements between computed tomography and magnetic resonance imaging studies in patients presenting with a femoroacetabular impingement-related complaint

Computed tomography (CT) is considered the gold standard for femoral version measurement. However, recent data have shown magnetic resonance imaging (MRI) as another modality to measure femoral version. This study aimed to correlate MRI and CT femoral version measurements in patients presenting with a femoroacetabular impingement (FAI)-related complaint. Patients (18-35 years old) who presented to the hip preservation clinic and radiology department with a suspected FAI diagnosis from 26 December 2018 to 4 March 2020 were included. All patients had a CT and MRI of the hip, with images including both hips and knees, as per our institution's protocol for possible hip preservation surgery. Patients were excluded if they were missing views of the knees, or if they had a history or imaging appearance of any condition affecting femoral version at the femoral head (e.g. slipped capital femoral epiphysis). Femoral version was measured by three reviewers. Fifty-eight patients were included, and 36 (62%) were female. Femoral version averaged 6.1° ± 11.8° on CT and 6.5° ± 10.8° on MRI. A strong positive correlation was reported between the two imaging modalities (r: 0.81; P < 0.001). Inter-rater reliability among the three reviewers was excellent and statistically significant for measurements on both MRI [intraclass correlation coefficient (ICC): 0.95; 95% CI: 0.85, 0.99; P < 0.001] and CT (ICC: 0.97; 95% CI: 0.92, 0.99; P < 0.001). Our finding suggests that MRI is a sufficient method for measuring femoral version to determine disease etiology and treatment progression. To avoid exposing patients to ionizing radiation, physicians should not obtain CT scans to evaluate femoral version.

Femoral de-rotation osteotomy versus hip arthroscopy for management of femoroacetabular impingement in adult patients with decreased femoral anteversion: a matched retrospective cohort study

Femoral de-rotation osteotomy (FDO) and hip arthroscopy are both recognized surgical options for the management of femoroacetabular impingement (FAI) in the setting of decreased femoral anteversion (<5°). Minimal comparative data exist regarding the difference in outcomes between these two techniques, and we believe this is the first study to provide that comparison. This retrospective cohort study included a total of 20 patients with such pathology, matched for age, gender and body mass index. A total of 10 patients were included in the FDO group [median anteversion −0.5° (true retroversion); average follow-up 17.9 months]. In total, 10 patients were included in the hip arthroscopy group [median anteversion −0.5° (true retroversion); average follow-up 28.5 months]. Both groups demonstrated statistically and clinically significant improvement in the post-operative International Hip Outcome Tool (iHOT-33) scores [median improvement: FDO group, 37.7 points (r 14–58.8; P < 0.041); hip arthroscopy group, 35.9 points (r 11.1–81; P < 0.05)], noting that the minimal clinically important difference for the iHOT-33 is 6.1 points. However, the study was not adequately powered to delineate a difference in improvement between the two groups. The findings suggest significant improvement in patient-reported outcomes, and clinical findings can be achieved with either FDO or hip arthroscopy for FAI in the setting of decreased femoral anteversion. However, selection of the most suitable surgical procedure using a patient-specific approach may optimize outcomes in this challenging population.

Do femoral version abnormalities play a role in hip function of patients with hip pain?

BACKGROUND

A high prevalence of femoral version abnormalities has been observed in hip pain patients, with impact on hip range of motion and muscle strength that should be elucidated.

METHODS

Cross-sectional study. Thirty-one patients with hip pain (16 men and 15 female) were subjected to Biplanar X-Rays to quantify femoral version using three-dimensional measurements. The 62 hips were divided into normal version (10-20°, n = 18), anteverted (>20°, n = 19), and retroverted (<10°, n = 25). Joint range of motion for flexion, internal rotation, and external rotation was assessed through digital goniometry. Maximal isometric hip strength (flexion, extension, internal rotation, external rotation at 0° and 30°, abduction, adduction) was evaluated through hand-held dynamometry. Hip rotation index was calculated as external rotation minus internal rotation.

FINDINGS

Anteverted hips had greater internal rotation, while retroverted hips had greater external rotation (p = 0.001). Anteverted hips were weaker than retroverted hips for external rotation at 30° (p < 0.001), abduction (p = 0.006) and adduction (p < 0.001), and weaker than normal version hips for extension (p = 0.018). All three groups had different rotation index: retroverted>normal>anteverted (p < 0.001). The ordinal logistic regression found higher values of rotation index with higher probability of being retroverted (common odds ratio = 1.20). There was a strong correlation between femoral version group and rotation index (r_S = 0.76, p < 0.001). There was probability >70% of a hip being anteverted if the rotation index was <11°, and being retroverted if the index was >40°.

INTERPRETATION

Range of motion and muscle strength differed in hips with different femoral versions. The hip rotation index was a strong femoral version predictor.

Increased Femoral Anteversion Does Not Lead to Increased Joint Forces During Gait in a Cohort of Adolescent Patients

Orthopedic complications were previously reported for patients with increased femoral anteversion. A more comprehensive analysis of the influence of increased femoral anteversion on joint loading in these patients is required to better understand the pathology and its clinical management. Therefore, the aim was to investigate lower-limb kinematics, joint moments and forces during gait in adolescent patients with increased, isolated femoral anteversion compared to typically developing controls. Secondly, relationships between the joint loads experienced by the patients and different morphological and kinematic features were investigated. Patients with increased femoral anteversion (n = 42, 12.8 ± 1.9 years, femoral anteversion: 39.6 ± 6.9°) were compared to typically developing controls (n = 9, 12.0 ± 3.0 years, femoral anteversion: 18.7 ± 4.1°). Hip and knee joint kinematics and kinetics were calculated using subject-specific musculoskeletal models. Differences between patients and controls in the investigated outcome variables (joint kinematics, moments, and forces) were evaluated through statistical parametric mapping with Hotelling T2 and t-tests (α = 0.05). Canonical correlation analyses (CCAs) and regression analyses were used to evaluate within the patients’ cohort the effect of different morphological and kinematic predictors on the outcome variables. Predicted compressive proximo-distal loads in both hip and knee joints were significantly reduced in patients compared to controls. A gait pattern characterized by increased knee flexion during terminal stance (KneeFlex_tSt) was significantly correlated with hip and knee forces, as well as with the resultant force exerted by the quadriceps on the patella. On the other hand, hip internal rotation and in-toeing, did not affect the loads in the joints. Based on the finding of the CCAs and linear regression analyses, patients were further divided into two subgroups based KneeFlex_tSt. Patients with excessive KneeFlex_tSt presented a significantly higher femoral anteversion than those with normal KneeFlex_tSt. Patients with excessive KneeFlex_tSt presented significantly larger quadriceps forces on the patella and a larger posteriorly-oriented shear force at the knee, compared to patients with normal KneeFlex_tSt, but both patients’ subgroups presented only limited differences in terms of joint loading compared to controls. This study showed that an altered femoral morphology does not necessarily lead to an increased risk of joint overloading, but instead patient-specific kinematics should be considered.

Combined abnormalities of femoral version and acetabular version and McKibbin Index in FAI patients evaluated for hip preservation surgery

Frequencies of combined abnormalities of femoral version (FV) and acetabular version (AV) and of abnormalities of the McKibbin index are unknown. To investigate the prevalence of combined abnormalities of FV and AV and of abnormalities of the McKibbin index in symptomatic patients with femoroacetabular impingement (FAI), a retrospective, Institutional Review Board (IRB)-approved study of 333 symptomatic patients (384 hips) that were presented with hip pain and FAI was performed. The computed tomography/magnetic resonance imaging based measurement of central AV, cranial AV and FV was compared among five subgroups with distinguished FAI subgroups and patients that underwent a hip preservation surgery. The allocation to each subgroup was based on AP radiographs. Normal AV and FV were 10–25°. The McKibbin index is the sum of central AV and FV. Of patients that underwent a hip preservation surgery, 73% had a normal McKibbin index (20–50°) but 27% had an abnormal McKibbin index. Of all patients, 72% had a normal McKibbin index, but 28% had abnormal McKibbin index. The prevalence of combined abnormalities of FV and AV varied among subgroups: a higher prevalence of decreased central AV combined with decreased FV of patients with acetabular-retroversion group (12%) and overcoverage (11%) was found compared with mixed-type FAI (5%). Normal AV combined with normal FV was present in 41% of patients with cam-type FAI and in 34% of patients with overcoverage. Patients that underwent a hip preservation surgery had normal mean FV (17 ± 11°), central AV (19 ± 7°), cranial AV (16 ± 10°) and McKibbin index (36 ± 14°). Frequency of combined abnormalities of AV and FV differs between subgroups of FAI patients. Aggravated and compensated McKibbin index was prevalent in FAI patients. This has implications for open hip preservation surgery (surgical hip dislocation or femoral derotation osteotomy) or hip arthroscopy or non-operative treatment.

Hip Range of Motion Is Increased After Hip Arthroscopy for Femoroacetabular Impingement: A Systematic Review

Purpose

To investigate the impact of arthroscopic correction of symptomatic femoroacetabular impingement on postoperative hip range of motion (ROM), as an objectively measured postoperative clinically reported outcome.

Methods

A systematic review of the current literature was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. PubMed, OVID/MEDLINE, EMBASE, and Cochrane databases were queried in November 2020. Studies not reporting pre- to postoperative ROM measurements were excluded. Methodologic quality was assessed using the MINORS assessment, and certainty of evidence was assessed using the GRADE approach. Effect size using standardized mean differences assessed magnitude of change between pre- and postoperative ROM.

Results

In total, 23 studies were included evaluating 2,332 patients. Mean age ranged from 18 to 44.2 years. Flexion, internal rotation (IR), and external rotation (ER) were the predominantly measured ROMs reported in 91%, 100% and 65% of studies, respectively. Observed change following hip arthroscopy was considered significant in 57.1% (flexion), 74% (IR), and 20% (ER). Effect size of change in significantly improved ROMs were weak (16.7% flexion, 33.3% ER), moderate (58.3% flexion, 29.4% IR), and large (25% flexion, 64.7% IR, 66.7% ER). For goniometric assessment mean observed changes ranged as follows: flexion: 0.1° to 12.2°; IR: 3.6° to 21.9°; ER: –2.6° to 12.8°. For computed tomography–simulated assessment, the mean observed change ranged as follows: flexion: 3.0° to 8.0°; IR 9.3° to 14.0°.

Conclusions

Outcome studies demonstrate overall increased range of flexion and IR post-hip arthroscopy, with a moderate and large effect respectively. Change in ER is less impacted following hip arthroscopy. Certainty of evidence to support this observation is low. Current research evaluating changes in this functional ability is limited by a lack of prospective studies and non-standardized measurement evaluation techniques.

Level of Evidence

Level IV, systematic review of Level II-IV studies.

Artificial intelligence-based automatic assessment of lower limb torsion on MRI

Abnormal torsion of the lower limbs may adversely affect joint health. This study developed and validated a deep learning-based method for automatic measurement of femoral and tibial torsion on MRI. Axial T2-weighted sequences acquired of the hips, knees, and ankles of 93 patients (mean age, 13 ± 5 years; 52 males) were included and allocated to training (n = 60), validation (n = 9), and test sets (n = 24). A U-net convolutional neural network was trained to segment both femur and tibia, identify osseous anatomic landmarks, define pertinent reference lines, and quantify femoral and tibial torsion. Manual measurements by two radiologists provided the reference standard. Inter-reader comparisons were performed using repeated-measures ANOVA, Pearson’s r, and the intraclass correlation coefficient (ICC). Mean Sørensen-Dice coefficients for segmentation accuracy ranged between 0.89 and 0.93 and erroneous segmentations were scarce. Ranges of torsion as measured by both readers and the algorithm on the same axial image were 15.8°–18.0° (femur) and 33.9°–35.2° (tibia). Correlation coefficients (ranges, .968 ≤ r ≤ .984 [femur]; .867 ≤ r ≤ .904 [tibia]) and ICCs (ranges, .963 ≤ ICC ≤ .974 [femur]; .867 ≤ ICC ≤ .894 [tibia]) indicated excellent inter-reader agreement. Algorithm-based analysis was faster than manual analysis (7 vs 207 vs 230 s, p < .001). In conclusion, fully automatic measurement of torsional alignment is accurate, reliable, and sufficiently fast for clinical workflows.

Short-term Outcomes of Concomitant Femoral Derotation Osteotomy and Hip Arthroscopy

The goal of this study is to report the short-term outcomes of concomitant hip arthroscopy and femoral derotational osteotomy (FRO) to treat femoral malrotation and intra-articular pathology. Data were retrospectively reviewed for patients undergoing concomitant hip arthroscopy and FRO between March 2013 and January 2017. Patients were included if they had a minimum of 1 year of follow-up for modified Harris Hip Score (mHHS), Nonarthritic Hip Score (NAHS), Hip Outcome Score-Sports Specific Subscale (HOS-SSS), International Hip Outcome Tool (iHOT-12) score, 12-item Short Form Health Survey Physical component and Mental component (SF-12 P and SF-12 M, respectively) scores, Veterans RAND 12-item Health Survey Physical and Mental (VR-12 P and VR-12 M, respectively) scores, visual analog scale (VAS) score for pain, and patient satisfaction ratings. Rates for meeting the patient acceptable symptomatic state (PASS) and minimal clinically important difference (MCID) were also recorded. Nine hips were included, and mean follow-up was 36.9 months. Mean preoperative femoral version was 33.0°. Patients underwent 1 or more concomitant procedures, such as labral treatment, capsular plication, acetabuloplasty, or femoroplasty. At latest follow-up, significant improvement was seen for mHHS, NAHS, HOS-SSS, and VAS score. Additionally, rates of meeting the PASS for mHHS, iHOT-12 score, and HOS-SSS were 100%, 88.9%, and 55.6%, respectively. Rates of achieving MCID for mHHS and HOS-SSS were 77.8% and 66.7%, respectively. One hip required revision derotational osteotomy to treat overcorrection, and 3 hips underwent secondary surgery for hardware removal. Concomitant hip arthroscopy and FRO may yield improved outcomes for patients with concurrent intra-articular pathology and excessive femoral anteversion. Considering that no major complications were diagnosed, this procedure is also relatively safe. [Orthopedics. 2021;44(6):e739-e746.].

Clinically Significant Outcome Improvement After Hip Arthroscopy in Patients With Femoroacetabular Impingement Syndrome and Severe Femoral Torsion

Background:

The influence of femoral torsion on clinically significant outcome improvement after hip arthroscopy for femoroacetabular impingement syndrome (FAIS) has not been well-studied.

Purpose:

To quantify femoral torsion in FAIS patients using magnetic resonance imaging (MRI) and explore the relationship between femoral torsion and clinically significant outcome improvement after hip arthroscopy.

Study Design:

Cohort study; Level of evidence, 3.

Methods:

Included were patients who underwent hip arthroscopy for FAIS between January 2012 and August 2018 and had 2-year follow-up and preoperative MRI scans containing transcondylar slices of the knee. Participants were categorized as having severe retrotorsion (SR; <0°), normal torsion (NT; 0°-25°), and severe antetorsion (SA; >25°) as measured on MRI. Patient-reported outcomes (PROs) included the Hip Outcome Score–Activities of Daily Living, Hip Outcome Score–Sports Subscale, modified Harris Hip Score, 12-item International Hip Outcome Tool (iHOT-12), and visual analog scale (VAS) for pain and satisfaction. Achievement of Patient Acceptable Symptom State (PASS) and substantial clinical benefit (SCB) were analyzed among cohorts.

Results:

Included were 183 patients (SR, n = 13; NT, n = 154; SA, n = 16) with a mean age, body mass index, and femoral torsion of 30.6 ± 12.1 years, 24.0 ± 4.4 kg/m², and 12.55° ± 9.58°, respectively. The mean torsion was –4.5° ± 2.6° for the SR, 12.1° ± 6.8° for the NT, and 31.0° ± 3.6° for the SA group. There were between-group differences in the proportion of patients who achieved PASS and SCB on the iHOT-12, pain VAS, and any PRO (P < .05). Post hoc analysis indicated that the SA group achieved lower rates of PASS and SCB on the iHOT-12 and pain VAS, and lower rates of PASS on any PRO versus the SR group (P < .05); the SR group achieved higher rates of PASS and SCB on pain VAS scores versus the NT group (P = .003).

Conclusion:

The orientation and severity of femoral torsion during hip arthroscopy influenced the propensity for clinically significant outcome improvement. Specifically, patients with femoral retrotorsion and femoral antetorsion had higher and lower rates of clinically significant outcome improvement, respectively.

Subject-Specific Modeling of Femoral Torsion Influences the Prediction of Hip Loading During Gait in Asymptomatic Adults

Hip osteoarthritis may be caused by increased or abnormal intra-articular forces, which are known to be related to structural articular cartilage damage. Femoral torsional deformities have previously been correlated with hip pain and labral damage, and they may contribute to the onset of hip osteoarthritis by exacerbating the effects of existing pathoanatomies, such as cam and pincer morphologies. A comprehensive understanding of the influence of femoral morphotypes on hip joint loading requires subject-specific morphometric and biomechanical data on the movement characteristics of individuals exhibiting varying degrees of femoral torsion. The aim of this study was to evaluate hip kinematics and kinetics as well as muscle and joint loads during gait in a group of adult subjects presenting a heterogeneous range of femoral torsion by means of personalized musculoskeletal models. Thirty-seven healthy volunteers underwent a 3D gait analysis at a self-selected walking speed. Femoral torsion was evaluated with low-dosage biplanar radiography. The collected motion capture data were used as input for an inverse dynamics analysis. Personalized musculoskeletal models were created by including femoral geometries that matched each subject’s radiographically measured femoral torsion. Correlations between femoral torsion and hip kinematics and kinetics, hip contact forces (HCFs), and muscle forces were analyzed. Within the investigated cohort, higher femoral antetorsion led to significantly higher anteromedial HCFs during gait (medial during loaded stance phase and anterior during swing phase). Most of the loads during gait are transmitted through the anterior/superolateral quadrant of the acetabulum. Correlations with hip kinematics and muscle forces were also observed. Femoral antetorsion, through altered kinematic strategies and different muscle activations and forces, may therefore lead to altered joint mechanics and pose a risk for articular damage. The method proposed in this study, which accounts for both morphological and kinematic characteristics, might help in identifying in a clinical setting patients who, as a consequence of altered femoral torsional alignment, present more severe functional impairments and altered joint mechanics and are therefore at a higher risk for cartilage damage and early onset of hip osteoarthritis.

Association Between Orientation and Magnitude of Femoral Torsion and Propensity for Clinically Meaningful Improvement After Hip Arthroscopy for Femoroacetabular Impingement Syndrome: A Computed Tomography Analysis

BACKGROUND

Femoral torsion imaging measurements and classifications are heterogeneous throughout the literature, and the influence of femoral torsion on clinically meaningful outcome improvement after hip arthroscopy for femoroacetabular impingement syndrome (FAIS) has not been well studied.

PURPOSE

To (1) perform a computed tomography (CT)-based analysis to quantify femoral torsion in patients with FAIS and (2) explore the relationship between the orientation and magnitude of femoral torsion and the propensity for clinically meaningful outcome improvement after hip arthroscopy.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

Consecutive patients who underwent hip arthroscopy for FAIS between January 2012 and April 2018 were identified. Inclusion criteria were the presence of preoperative CT imaging with transcondylar slices of the knee and minimum 2-year outcome measures. Exclusion criteria were revision hip arthroscopy, Tönnis grade >1, congenital hip condition, hip dysplasia (lateral center-edge angle <20°), and concomitant gluteus medius or minimus repair. Torsion groups were defined as severe retrotorsion (SR; <0°), moderate retrotorsion (MR; 0°-5°), normal torsion (N; 5°-20°), moderate antetorsion (MA; 20°-25°), and severe antetorsion of antetorsion (SA; >25°). Treatment did not differ based on femoral torsion. Patient characteristics and clinical outcomes were analyzed, including the Hip Outcome Score-Activities of Daily Living (HOS-ADL), Hip Outcome Score-Sports Subscale (HOS-SS), modified Harris Hip Score (mHHS), international Hip Outcome Tool (iHOT-12), visual analog scale (VAS) for pain, and VAS for satisfaction. Achievement of the minimal clinically important difference (MCID) and patient acceptable symptom state (PASS) by torsion stratification was analyzed using the chi-square test. Inter- and intrarater reliabilities for CT measurements were 0.980 (P < .001) and 0.974 (P < .001), respectively.

RESULTS

The study included 573 patients with a mean ± SD age and body mass index of 32.6 ± 11.8 years and 25.6 ± 10.6, respectively. The mean ± SD femoral torsion for the study population was 12.3°± 9.3°. After stratification, the number of patients within each group and the mean ± SD torsion for each group were as follows: SR (n = 36; -6.5°± 7.1°), MR (n = 80; 2.8°± 1.4°), N (n = 346; 12.3°± 4.1°), MA (n = 64; 22.2°± 1.4°), and SA (n = 47; 30.3°± 3.7°). No significant differences in age, body mass index, sex, tobacco use, workers' compensation status, or participation in physical activity were observed at baseline. No significant differences were seen in pre- and postoperative VAS pain, mHHS, HOS-ADL, HOS-SS, iHOT-12, or postoperative VAS satisfaction among the cohorts. Furthermore, no statistically significant differences were found in the proportion of patients who achieved the MCID or the PASS for any outcome among the groups.

CONCLUSION

The orientation and severity of femoral torsion at the time of hip arthroscopy for FAIS did not influence the propensity for clinically significant outcome improvement.

Influence of Femoral Version on the Outcomes of Hip Arthroscopic Surgery for Femoroacetabular Impingement or Labral Tears: A Systematic Review and Meta-analysis

BACKGROUND

It remains controversial whether abnormal femoral version (FV) affects the outcomes of hip arthroscopic surgery for femoroacetabular impingement (FAI) or labral tears.

PURPOSE

To review the outcomes of hip arthroscopic surgery for FAI or labral tears in patients with normal versus abnormal FV.

STUDY DESIGN

Systematic review; Level of evidence, 4.

METHODS

Embase, PubMed, and the Cochrane Library were searched in July 2020 for studies reporting the outcomes after primary hip arthroscopic surgery for FAI or labral tears in patients with femoral retroversion (<5°), femoral anteversion (>20°), or normal FV (5°-20°). The primary outcome was the modified Harris Hip Score (mHHS), and secondary outcomes were the visual analog scale (VAS) for pain, Hip Outcome Score-Sport-Specific Subscale (HOS-SSS), Non-Arthritic Hip Score (NAHS), failure rate, and patient satisfaction. The difference in preoperative and postoperative scores (Δ) was also calculated when applicable.

RESULTS

Included in this review were 5 studies with 822 patients who underwent hip arthroscopic surgery for FAI or labral tears; there were 166 patients with retroversion, 512 patients with normal version, and 144 patients with anteversion. Patients with retroversion and normal version had similar postoperative mHHS scores (mean difference [MD], 2.42 [95% confidence interval (CI), -3.42 to 8.26]; P = .42) and ΔmHHS scores (MD, -0.70 [96% CI, -8.56 to 7.15]; P = .86). Likewise, the patients with anteversion and normal version had similar postoperative mHHS scores (MD, -3.09 [95% CI, -7.66 to 1.48]; P = .18) and ΔmHHS scores (MD, -1.92 [95% CI, -6.18 to 2.34]; P = .38). Regarding secondary outcomes, patients with retroversion and anteversion had similar ΔNAHS scores, ΔHOS-SSS scores, ΔVAS scores, patient satisfaction, and failure rates to those with normal version, although a significant difference was found between the patients with retroversion and normal version regarding postoperative NAHS scores (MD, 5.96 [95% CI, 1.66-10.26]; P = .007) and postoperative HOS-SSS scores (MD, 7.32 [95% CI, 0.19-14.44]; P = .04).

CONCLUSION

The results of this review indicated that abnormal FV did not significantly influence outcomes after hip arthroscopic surgery for FAI or labral tears.

Outcomes of femoral de-rotation osteotomy for treatment of femoroacetabular impingement in adults with decreased femoral anteversion

Decreased femoral anteversion is an often overlooked factor in femoroacetabular impingement (FAI), with potential to exacerbate both cam and pincer type impingement, or itself be the primary cause. Femoral de-rotation osteotomy (FDO) is a surgical option for symptomatic patients with such underlying bony deformity. This study aimed to investigate outcomes of FDO for management of symptomatic FAI in the presence of decreased (<5°) femoral anteversion. Secondary aims were to describe the surgical technique and assess complications. This study included 33 cases (29 patients) with average pre-operative anteversion measuring –3.1° (true retroversion). At an average follow-up of 1.5 years (19.8 months), 97% reported significant improvement. The overall average post-operative International Hip Outcome Tool (iHOT-33) score of 70.6 points (r: 23–98) compared to the average pre-operative score of 42.8 points (r: 0–56) for the 11 patients with available pre-operative scores suggests an overall improvement. The minimal clinically important difference for the iHOT-33 is 6.1 points. Patients with both pre- and post-operative iHOT-33 scores available demonstrated a statistically and clinically significant improvement of 37.7 (r: 13–70) points. There were three cases (9%) of delayed union and two cases (6%) of non-union early in the series which prompted evolution of the technique. Locking screw removal was performed in 33% of patients for a resultant overall re-operation rate of 45%. The findings suggest improvement in patient-reported outcomes can be achieved with FDO for symptomatic FAI in the setting of decreased femoral anteversion (<5°).

Morphological Changes of the Hip Commonly Associated With Femoroacetabular Impingement Are Not Correlated With Rotational Range of Hip Motion in Elite Soccer Athletes

BACKGROUND

Morphological changes characteristic of femoroacetabular impingement (FAI) are common in soccer players. However, the clinical relevance of such anatomical variations is still not well-defined.

HYPOTHESIS

We hypothesized that high alpha angle values and/or acetabular retroversion index (ARI) are correlated with rotational range of motion (ROM) of the hip and that there are clinical-radiological diferences between the dominant lower limb (DLL) and nondominant lower limb (NDLL) in professional soccer players.

STUDY DESIGN

Cross-sectional.

LEVEL OF EVIDENCE

Level 3.

METHODS

A total of 59 male professional soccer players (average age 25.5 years, range 18-38 years) were evaluated in the preseason. As main outcome measures, we evaluated the alpha angle and the ARI and hip IR and ER ROM with radiographic analysis.

RESULTS

The measurements taken on DLL and NDLL were compared and a significant difference was found between the sides in the ER (P = 0.027), where the DLL measures were 1.54° (95% CI, 0.18-2.89) greater than the NDLL. There were no significant differences between the sides in the measures of IR (P > 0.99), total ROM (P = 0.07), alpha angle (P = 0.250), and ARI (P = 0.079). The correlations between the rotation measurements and the alpha angle in each limb were evaluated and the coefficient values showed no correlation; so also between the ARI and rotation measures.

CONCLUSION

Morphological changes of the femur or acetabulum are not correlated with hip IR and ER ROM in male professional soccer players. ER on the dominant side was greater than on the nondominant side. There was no significant difference in the other measurements between sides.

CLINICAL RELEVANCE

In clinical practice, it is common to attribute loss of hip rotational movement to the presence of FAI. This study shows that anatomical FAI may not have a very strong influence on available hip rotational movement in professional soccer athletes.

Over one third of patients with symptomatic femoroacetabular impingement display femoral or acetabular version abnormalities

PURPOSE

The aim of this study was investigate the relationship between version and torsional abnormalities of the acetabulum, femur and tibia in patients with symptomatic FAI.

METHODS

A systematic review was performed according to PRISMA guidelines using the EMBASE, MEDLINE, PubMed and Cochrane databases. Original research articles evaluating the described version and torsional parameters in FAI were included. The MINORS criteria were used to appraise study quality and risk of bias. Mean version and torsion values were displayed using forest plots and the estimated proportion of hips displaying abnormalities in version/torsion were calculated.

RESULTS

A total of 1206 articles were identified from the initial search, with 43 articles, involving 8861 hips, meeting the inclusion criteria. All studies evaluating femoral or acetabular version in FAI reported 'normal' mean version values (10-25 °). However, distribution analysis revealed that an estimated 31% and 51% of patients with FAI displayed abnormal central acetabular and femoral version, respectively.

CONCLUSION

Up to 51% of patients presenting with symptomatic FAI show an abnormal femoral version, whilst up to 31% demonstrate abnormal acetabular version. This high percentage of version abnormalities highlights the importance of evaluating these parameters routinely during assessment of patients with FAI, to guide clinical decision-making.

LEVEL OF EVIDENCE

IV.

Patient-specific factors are associated with severity of chondrolabral injury in patients with femoroacetabular impingement

PURPOSE

The purpose of this study was to evaluate the relationship between patient-specific factors, preoperative radiographic findings, and the presence and severity of chondrolabral damage identified during hip arthroscopy for femoroacetabular impingement.

METHODS

Between 2014 and 2017, patients who underwent hip arthroscopy for FAI and labral tear were retrospectively reviewed. Patient-specific variables including age, gender, BMI, LCEA, and alpha angle were collected. Surgical reports were reviewed for labral tear position and size, as well as severity of acetabular and femoral chondromalacia.

RESULTS

There were 205 patients who met inclusion criteria with a mean age of 33 years (range 15-66), BMI 26.5 (range 15.9-44.5), LCEA 32.2° (range 21.0°-56.0°) and alpha angle 59.1° (range 33.0°-86.0°). Greater age (p = 0.023), alpha angle (p = 0.011) and male gender (p < 0.001) significantly correlated with high-grade acetabular chondral damage. Increased LCEA (p < 0.001), increased alpha angle (p = 0.012), and greater age (p = 0.002) were significantly associated with increased labral tear size.

CONCLUSIONS

Greater age, male gender, increased BMI and increased alpha angle were associated with more advanced acetabular chondromalacia. Additionally, greater age, increased LCEA, and increased alpha angle was associated with larger labral tear size.

LEVEL OF EVIDENCE

IV.

Femoral torsion evaluation by computed tomography in a young Brazilian population with hip pain and femoroacetabular impingement

Introduction

The aim of the study was to evaluate femoral torsion (FT) by computed tomography (CT) in young patients with hip pain and femoroacetabular impingement (FAI) in a Brazilian population. After the diagnosis of impingement, the complete analysis from the hip biomechanics and morphology has become essential.

Methods

Forty-one patients from 18 to 45 years presenting hip pain without arthrosis (Tönnis<2) were evaluated by CT scan from February 2017 to February 2018. All patients presented hip pain for at least 3 months and FAI. They have followed the same radiographic protocol and modified Harris Hip Score (mHHS) evaluation. Statistical analyses by software R version 3.4.4. with significance p < 0,05.

Results

After exclusion criterias, twenty-six patients (9 bilateral) were included, mostly man (73%). The average age was 35 years for both genders. BMI was 19 kg/m2 for women and 24 kg/m2 for men and the mean modified Harris Hip Score was 67 points. We have found femoral torsion changes in 11 hips with pain (31%) and high variability (60%). The mean FT was 14,5°, ranging from 0 to 39°. Patients with hip pain, CAM impingement and altered FT had no correlation when compared to controls (without pain) (p = 0.234), neither Mixed impingement (p = 0.314). Patients with Pincer impingement and painful hips had higher FT (16,63°) than controls (11,77°) (p = 0.045). Conclusion: The presence of torsional alterations in almost 1/3 of the patients with FAI and the high variability reveal the importance of measuring FT at this disease.

Hip morphology and its relationship with hip strength, mobility and lower limb biomechanics: a systematic review in adults

Abstract This systematic review (PROSPERO registration n.43640) aimed to summarise and determine the quality of evidence relating hip bone morphology to (i) hip strength, (ii) mobility and (iii) lower limb biomechanics during functional activities. A standardized search on MEDLINE/PubMed, Web of Science, ScienceDirect and Scopus resulted in 17 papers that met inclusion criteria: i) original investigations with a minimal sample of n=10, ii) studies on humans and iii) presence of at least one quantitative hip morphological parameter and one hip functional (i.e. strength and mobility) and/or one lower limb biomechanical parameter. Risk of bias was assessed using the Quality Assessment of Diagnostic Accuracy Studies tool with adaptations. Sixteen out of the 17 included studies showed high risk of bias. We observed that primary evidence pointed to the influence of hip morphology on hip mobility in the transverse plane. Specifically, positive correlations between femoral anteversion angle and range of internal hip rotation in physical examination were observed. Regarding biomechanical parameters, no clear evidence of association between hip morphology, and kinematic and kinetic parameters were found. Our results point to a field that is currently under explored and future studies with low risk of bias addressing these relationships are required.

Etiology and Pathomechanics of Femoroacetabular Impingement

PURPOSE OF REVIEW

Femoroacetabular impingement is a common cause of hip pain in young patients and has been shown to progress to osteoarthritis. The purpose of this review is to better understand the development of femoroacetabular impingement.

RECENT FINDINGS

Recent literature shows little genetic transmission of FAI. However, molecular studies show strong similarities with the cartilage in osteoarthritis. The development of cam lesions has a strong association with sports participation, particularly at the time of physeal closure suggesting abnormal development. Lumbar, pelvis, and femoral biomechanics may also play an important role in dynamic impingement. In summary, femoroacetabular impingement is a dynamic process with many influences. Further research is needed to clarify the pathophysiology of FAI development in hopes of finding preventative options to reduce symptoms and progression to osteoarthritis.

Clinical and Radiographic Predictors for Unsalvageable Labral Tear at the Time of Initial Hip Arthroscopic Management for Femoroacetabular Impingement

BACKGROUND

The acetabular labrum plays important roles in proprioception, nociception, synovial fluid seal effect, and static and dynamic joint stability and as a shock absorber. Clinical and radiographic risk factors for unsalvageable labral tear in femoroacetabular impingement (FAI) are not well established.

PURPOSE

To identify predictors of unsalvageable labral tear during initial hip arthroscopic management of FAI.

STUDY DESIGN

Case-control study; Level of evidence, 3.

METHODS

Patients were included who underwent primary hip arthroscopic treatment for FAI between March 2009 and March 2014. Patients were excluded who had <2-year follow-up, underwent bilateral surgery, or had a history of surgery, osteoarthritis (Tönnis grade 2 or 3), and other diagnoses, including lateral center-edge angle <25° diagnosed as developmental hip dysplasia. Patients were divided into 2 groups according to their labral condition: reconstruction and refixation. Unsalvageable labral tear was defined as any irreparable labral tear, including severe degenerative tear, frayed labrum, labral ossification, flattened labrum, and failed prior repair during surgery. Univariate and multivariate analyses identified risk factors for segmental labral reconstruction. Patient-reported outcome scores and postoperative revision rates were also assessed.

RESULTS

Twenty-five hips (18 male, 7 female) and 126 hips (65 male, 61 female) were included in the reconstruction and refixation groups, respectively. The mean ± SD ages were 52.6 ± 15.0 and 36.5 ± 16.1 years in the reconstruction and refixation groups, respectively. In the reconstruction group, the mean modified Harris Hip Score significantly improved from 67.3 ± 14.9 preoperatively to 95.0 ± 8.1 at final follow-up (P < .001), and the mean Nonarthritic Hip Score improved from 63.0 ± 18.3 preoperatively to 89.5 ± 10.1 at final follow-up (P < .001). In the refixation group, the mean modified Harris Hip Score significantly improved from 69.2 ± 18.6 preoperatively to 93.0 ± 11.2 at final follow-up (P < .001), and the mean Nonarthritic Hip Score improved from 60.7 ± 18.8 preoperatively to 88.6 ± 15.0 at final follow-up (P < .001). No significant difference was noted in patient-reported outcome scores and revision hip arthroscopy rates. The rate of conversion of total hip arthroplasty was higher in the reconstruction group than in the refixation group. Risk factors for unsalvageable labral tear were age ≥45 years (odds ratio [OR], 8.83; P < .007), body mass index ≥23.1 kg/m² (OR, 13.05; P < .001), and vertical center anterior angle ≥36° (OR, 19.03; P < .001). Furthermore, in this study, unsalvageable labral tears were present in cases with at least 2 of the 3 risk factors.

CONCLUSION

Age ≥45 years, body mass index ≥23.1 kg/m², and vertical center anterior angle ≥36° are risk factors for unsalvageable labral tear at initial hip arthroscopic surgery for patients with FAI.

CLINICAL RELEVANCE of the LIGAMENTUM TERES: A LITERATURE REVIEW

Background

The ligamentum teres (LT) continues to be a structure of debate and interest. Previously thought of as a vestigial structure, an awareness of LT pathology and its potential importance has increased with the expansion of hip arthroscopy.

Purpose

To provide a comprehensive literature synthesis on the LT and provide clinicians with the most current research regarding the LT and its anatomical features, functional relevance, prevalence of injury, risk factors for injury, clinical presentation, and treatment for pathology.

Methods

A systematic literature search was conducted using Medline/PubMed, CINAHL/EBSCO, and Cochrane/Wiley databases/platforms using the following search terms: ligament, ligament teres, hip, femur, femoral head, round ligament.

Results

This search yielded 1284 articles of which 44 met the inclusion/exclusion criteria and contributed to this manuscript. Information on the LT was summarized into the following areas: anatomy, function, injury prevalence, risk factors, mechanism of injury, duration of symptoms, clinical presentation (symptoms, range of motion, functional limitations, special testing), imaging, and treatment.

Conclusions

The results of this review supported the following: 1) the LT has a function in restraining hip rotation range of motion; 2) the prevalence of LT pathology in any given population may be largely dependent on the severity of bony deformity (either femoroacetabular impingement(FAI) or dyplasia) and activity level; 3) older age and acetabular bony deformity (either FAI or dyplasia) are risk factors for generalized LT pathology; 4) unique signs and symptoms are difficult to identify because LT pathology rarely occurs in isolation and is likely the end-stage consequence of other hip pathology; 5) the presence of LT pathology may negatively affect an individual's ability to function; and 6) surgical debridement is recommend for pain relief of partial LT tears with reconstruction possible for complete LT tears when complaints of instability are noted.

Level of Evidence

3.

Clinical tests to determine femoral version category in people with chronic hip joint pain and asymptomatic controls

STUDY DESIGN

Controlled laboratory cross-sectional.

OBJECTIVES

To investigate the relationship between femoral version (FV), measured by MRI (FVMRI), Craig's test and hip rotation range of motion (ROM). To determine rotation ROM values associated with FVMRI categories: excessive anteversion, normal version and retroversion.

BACKGROUND

Abnormal FV values are associated with hip disorders, such as osteoarthritis, structural instability, acetabular labral tears and femoroacetabular impingement. Clinical assessment of FV may allow clinician to identify the effect of bony abnormalities on hip rotation ROM to guide clinical decisions.

METHODS

Thirty-eight participants with chronic hip joint pain (CHJP) and 38 matched controls participated. MRI was used to determine FVMRI. A digital inclinometer was used to assess Craig's test, hip internal rotation (IR) and external rotation (ER) with hip flexed to 90° (90°), and hip IR/ER with hip in neutral flexion/extension (0°). ROM differences (ROMdif) were determined by subtracting ER from IR. Pearson correlation coefficients were used to assess the relationship between FVMRI and clinical variables. One-way analysis of variance (ANOVA) was used to compare rotation ROM among FVMRI categories.

RESULTS

There were no differences between CHJP and control groups in demographics, FVMRI, Craig's test or ROM. ROMdif0° showed the highest correlation (r = 0.63) with FVMRI, then IR90° (r = 0.61) and Craig's test (r = 0.61). Differences were noted among FVMRI categories for rotation ROM except hip ER90°.

CONCLUSION

Hip rotation ROM and Craig's test may be used for screening when imaging is not indicated. A 20° difference between hip IR and ER ROM would be suggestive of abnormal FV.

Normative data on femoral version

Femoral version is reported to vary in relation to age, gender and other patient-specific factors. Differences in femoral version are suspected to contribute to the development of hip pathology. However, normative data on pathologic hips has never been reported. To evaluate the femoral version in a large population of patients with symptomatic hip pathology treated with arthroscopy and report differences within this group based on age, gender, bony morphology and other hip-related factors. A prospectively gathered database of 1449 hips was reviewed. All patients underwent pre-operative MRI with measure of femoral version. The average femoral version of the entire population was 8.4+ 9.2°, range −23 to 63. There no statistically significant differences encountered based on age, gender, bony morphology or other hip-related factors. Across all groups, there was wide variation in the femoral version present. Among younger patients, there was trend to have a greater proportion of retroversion. Significant variation in femoral version exists in patients with symptomatic hip pathology. Although the geometry of the proximal femur is commonly described as anteverted, relative retroversion is also frequently encountered.

Femoral Derotation Osteotomy in Adults for Version Abnormalities

BACKGROUND

Version abnormalities of the femur can cause pain and hip joint damage due to impingement or instability. A retrospective clinical review was conducted on patients undergoing a subtrochanteric derotation osteotomy for either excessive anteversion or retroversion of the femur.

METHODS

A total of 55 derotation osteotomies were performed in 43 patients: 36 females and 7 males. The average age was 29 years (range, 14 to 59 years). The osteotomies were performed closed with an intramedullary saw. Fixation was performed with a variety of intramedullary nails. Twenty-nine percent of patients had a retroversion deformity (average, -9° of retroversion; range, +2° to -23°) and 71% had excessive anteversion of the femur (average, +37° of anteversion; range, +22° to +53°). The etiology was posttraumatic in 5 patients (12%), diplegic cerebral palsy in 2 patients (5%), Prader-Willi syndrome in 1 patient (2%), and idiopathic in 35 patients (81%). Forty-nine percent underwent concomitant surgery with the index femoral derotation osteotomy, including hip arthroscopy in 40%, tibial derotation osteotomy in 13%, and a periacetabular osteotomy in 5%. Tibial osteotomies were performed to correct a compensatory excessive external tibial torsion that would be exacerbated in the correction of excessive femoral anteversion.

RESULTS

No patient was lost to follow-up. Failures occurred in three hips in three patients (5%): two hip arthroplasties and one nonunion that healed after rerodding. There was one late infection treated successfully with implant removal and antibiotics with an excellent final clinical outcome. At an average follow-up of 6.5 years (range, 2 to 19.7 years), the modified Harris Hip Score improved by 29 points in the remaining 52 cases (P < 0.001, Wilcoxon signed-rank test). The results were rated as excellent in 75%, good in 23%, and fair in 2%. Subsequent surgery was required in 78% of hips, 91% of which were implant removals.

CONCLUSIONS

A closed, subtrochanteric derotation osteotomy of the femur is a safe and effective procedure to treat either femoral retroversion or excessive anteversion. Excellent or good results were obtained in 93%, despite the need for subsequent implant removal in more than two-thirds of the patients.

Advanced Concepts in Hip Morphology, Associated Pathologies, and Specific Rehabilitation for Athletic Hip Injuries

Hip and groin injuries comprise up to 17% of athletic injuries and can pose rehabilitation challenges for many athletes. Injuries involving abnormal femoral acetabular morphology, reduced range of motion, and decreased lumbopelvic strength and endurance also may increase the risk of injury to lower extremities and delay return to play if proper rehabilitation does not take place. The rehabilitation of athletic hip injuries requires a multifaceted interdisciplinary approach that manages the interplay of multiple factors to restore preinjury function and facilitate return to play. Emphasis should be placed on activity modification, preservation of the arcs of range of motion, functional strengthening of the lumbopelvic core, and optimization of proprioceptive and neuromechanical strategies. Communication between providers and the injured athlete also is crucial to ensure that proper therapeutic approaches are being applied.

Editorial Commentary: Caveat Flexor-To Release or Not to Release the Iliopsoas, That Is the Question

In nonarthritic patients with femoroacetabular impingement syndrome, borderline dysplasia, and symptomatic iliopsoas snapping, arthroscopic iliopsoas fractional lengthening carries a significant risk of postarthroscopic instability. The iliopsoas is a dynamic stabilizer of the anterior hip. Thus, although statistically significant and clinically important improvements in hip function have the potential to be achieved with iliopsoas fractional lengthening, surgeons must be supremely confident in their ability to perform a secure capsular plication, labral preservation (not debridement), comprehensive cam correction, avoidance of intra-abdominal fluid extravasation, release of all iliopsoas tendon bands (if bifid or trifid), and ensure that femoral version is normal or low, neck-shaft angle is not excessively valgus, the dysplasia magnitude is no more than mild, and that there is no excessive soft tissue hypermobility. If these goals can be met, then excellent outcomes can be achieved. If not, then an iliopsoas fractional lengthening should not be performed.

Anatomic Predictors of Sagittal Hip and Pelvic Motions in Patients With a Cam Deformity

BACKGROUND

As there is a high prevalence of patients with cam deformities and no ongoing hip dysfunction, understanding the biomechanical factors predicting the onset of symptoms and degenerative changes is critical. One such variable is how the spinopelvic parameters may influence hip and pelvic sagittal mobility. Hypothesis/Purpose: Pelvic incidence may predict sagittal hip and pelvic motions during walking and squatting. The purpose was to determine which anatomic characteristics were associated with symptoms and how they influenced functional hip and pelvic ranges of motion (ROMs) during walking and squatting.

STUDY DESIGN

Controlled laboratory study.

METHODS

Fifty-seven participants underwent computed tomography and were designated either symptomatic (n = 19, cam deformity with pain), asymptomatic (n = 19, cam deformity with no pain), or control (n = 19, no cam deformity or pain). Multiple femoral (cam deformity, neck angle, torsion), acetabular (version, coverage), and spinopelvic (pelvic tilt, sacral slope, pelvic incidence) parameters were measured from each participant's imaging data, and sagittal hip and pelvic ROMs during walking and squatting were recorded using a motion capture system.

RESULTS

Symptomatic participants had large cam deformities, smaller femoral neck-shaft angles, and larger pelvic incidence angles compared with the asymptomatic and control participants. Discriminant function analyses confirmed that radial 1:30 alpha angle (λ₁ = 0.386), femoral neck-shaft angle (λ₂ = 0.262), and pelvic incidence (λ₃ = 0.213) ( P < .001) were the best anatomic parameters to classify participants with their groups. Entering these 3 parameters into a hierarchical linear regression, significant regressions were achieved for hip ROM only when pelvic incidence was included for walking ( R² = 0.20, P = .01) and squatting ( R² = 0.14, P = .04). A higher pelvic incidence decreased walking hip ROM ( r = -0.402, P = .004). Although symptomatic participants indicated a trend of reduced squatting hip and pelvic ROMs, there were no significant regressions with the anatomic parameters.

CONCLUSION

A cam deformity alone may not indicate early clinical signs or decreased ROM. Not only was pelvic incidence a significant parameter to classify the participants, but it was also an important parameter to predict functional ROM. Symptomatic patients with a higher pelvic incidence may experience limited sagittal hip mobility.

CLINICAL RELEVANCE

Patients with symptomatic femoroacetabular impingement showed a higher pelvic incidence and, combined with a cam deformity and varus neck, can perhaps alter the musculature of their iliopsoas, contributing to a reduced sagittal ROM. With an early and accurate clinical diagnosis, athletes could benefit from a muscle training strategy to protect their hips.

Patient-Reported Outcomes of Capsular Repair Versus Capsulotomy in Patients Undergoing Hip Arthroscopy: Minimum 5-Year Follow-up-A Matched Comparison Study

PURPOSE

To elucidate whether capsular closure during hip arthroscopy affected patient outcomes over midterm follow-up.

METHODS

Between 2008 and 2011, data were prospectively collected and retrospectively reviewed on patients who underwent hip arthroscopy. Patients were then matched for age, gender, worker's compensation, body mass index, and acetabular coverage. The inclusion criteria were capsular repair or unrepaired capsulotomy, lateral-center edge angle ≥18°, and minimum 5-year follow-up. The exclusion criteria were previous hip surgery or conditions and Tönnis grade >1. Patient-reported outcome scores (PROs) included modified Harris hip score (mHHS), nonarthritic hip score, hip outcome score sport-specific subscale, and visual analog score for pain, which were collected preoperatively, at 3 months, and annually thereafter. Minimal clinical important difference (MCID) and patient acceptable symptomatic state (PASS) for both groups were analyzed. Patient satisfaction was noted as well as any complications, secondary surgery, and conversion to arthroplasty.

RESULTS

Minimum 5-year follow-up was available for 82.5% (287 of 348) hips that met the inclusion criteria and were eligible for matching. Ultimately, 65 patients who underwent capsular repair could be matched in a 1:1 ratio to 65 patients with release. Both groups had significant improvements in all mean PROs. The repair group had significant improvement of mean PROs, visual analog score, and patient satisfaction at both 2-year and minimum 5-year follow-up. The unrepaired group had a significant decrease in mHHS (P = .001) and patient satisfaction (P = .01) between 2- and 5-year follow-up. Despite decreasing mHHS in the repair group between 2- and 5-year follow-up, both groups met the MCID and PASS criteria with no significant difference between them. More patients in the release group required conversion to hip arthroplasty (18.5% vs 10.8%). Subgroup analysis considering various perioperative factors confirmed this trend. Rate of revision arthroscopy was the same in both groups (15.4%). Complication rate was low (4.6% vs 6.4%) in both groups.

CONCLUSIONS

Patients undergoing hip arthroscopy and who have minimal or no arthritis have significant short-term improvement, whether the capsule is closed or left unrepaired. However, at midterm follow-up, patients who had unrepaired capsules had deterioration in mHHS as well as a higher rate of conversion to arthroplasty, even when controlling for various perioperative variables. Despite this, patients in both groups met the MCID and PASS criteria. This study suggests that routine capsular closure may lead to more consistently durable outcome in patients undergoing hip arthroscopy, but also that individual patient pathology may dictate capsular management.

LEVEL OF EVIDENCE

Level III, retrospective comparative study.

Torsional Growth Modulation of Long Bones by Oblique Plating in a Rabbit Model

BACKGROUND

There is evidence that oblique tension band plating can affect torsional growth in long bones. This study sought to determine if the torsional growth could be modulated based on the angles of the tension band plating and whether or not oblique plating affected overall longitudinal growth.

METHODS

New Zealand White rabbits (10.5 wk old) had one screw placed on the metaphyseal side and one on the epiphyseal side of both medial and lateral sides of the right knee distal femoral physis. The sham group (n=5) included screw placement only. For the plate group (n=13), unlocked plates, angled from 0 to 76 degrees, connected the screws and spanned the physis. Radiographs were taken at biweekly intervals. After 6 weeks of growth, hindlimbs were harvested and microCT scans performed. Femoral length, distances between screw heads and angle between the plates were measured on radiographs. Femoral length differences were compared between groups. Femoral version was measured from 3D microCT. Plate angle changes were correlated to the difference in femoral version between limbs using Pearson correlation (significance was set to P<0.05 for all comparisons).

RESULTS

Femur length difference between the contralateral and the operative side was significantly greater in the plate group compared with the sham group over time (P=0.049). Medial and lateral screw distances changed significantly more in the sham group than the plate group on both sides (P<0.001). A greater initial angle between plates resulted in a greater change in the angle between plates (P<0.001). Significant correlations were found between right-left side femoral version differences and initial plate angle (P=0.003) and plate angle change (P=0.014).

CONCLUSIONS

The torsional effect of oblique plating seems to correlate with the amount of initial plate angle, with an additional, not negligible, longitudinal growth effect.

CLINICAL SIGNIFICANCE

Placing plates at given angles across open physes may result in predictable changes in bone torsion allowing for a safer and less invasive option when treating childhood torsional deformities, but the resulting shortening of the ipsilateral femur must be considered.

Hip Arthroscopic Surgery With Labral Preservation and Capsular Plication in Patients With Borderline Hip Dysplasia: Minimum 5-Year Patient-Reported Outcomes

BACKGROUND

The arthroscopic management of hip dysplasia has been controversial and has historically demonstrated mixed results. Studies on patients with borderline dysplasia, emphasizing the importance of the labrum and capsule as secondary stabilizers, have shown improvement in patient-reported outcomes (PROs). Purpose/Hypothesis: The purpose was to assess whether the results of hip arthroscopic surgery with labral preservation and concurrent capsular plication in patients with borderline hip dysplasia have lasting, positive outcomes at a minimum 5-year follow-up. It was hypothesized that with careful patient selection, outcomes would be favorable.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

Data were prospectively collected and retrospectively reviewed for patients aged <40 years who underwent hip arthroscopic surgery for intra-articular abnormalities. Inclusion criteria included lateral center-edge angle (LCEA) between 18° and 25°, concurrent capsular plication and labral preservation, and minimum 5-year follow-up. Exclusion criteria were severe dysplasia (LCEA ≤18°), Tönnis grade ≥2, pre-existing childhood hip conditions, or prior hip surgery. PRO scores including the modified Harris Hip Score (mHHS), Non-Arthritic Hip Score (NAHS), and Hip Outcome Score Sport-Specific Subscale (HOS-SSS) and the visual analog scale (VAS) score for pain were collected preoperatively, at 3 months, and annually thereafter. Complications and revisions were recorded.

RESULTS

Twenty-five hips (24 patients) met the inclusion criteria. Twenty-one hips (19 patients, 84%) were available for follow-up. The mean age at surgery was 22.9 years. The mean preoperative LCEA and Tönnis angle were 21.7° (range, 18° to 24°) and 6.9° (range, -1° to 16°), respectively. The mean follow-up was 68.8 months. The mean mHHS increased from 70.3 to 85.9 ( P < .0001), the mean NAHS from 68.3 to 87.3 ( P < .0001), and the mean HOS-SSS from 52.1 to 70.8 ( P = .0002). The mean VAS score improved from 5.6 to 1.8 ( P < .0001). Four hips (19%) required secondary arthroscopic procedures, all of which resulted in improved PRO scores at latest follow-up. No patient required conversion to total hip arthroplasty.

CONCLUSION

While periacetabular osteotomy remains the standard for treating true acetabular dysplasia, hip arthroscopy may provide a safe and durable means of managing intra-articular abnormalities in the setting of borderline acetabular dysplasia at midterm follow-up. These procedures should be performed by surgeons with expertise in advanced arthroscopic techniques, using strict patient selection criteria, with emphasis on labral preservation and capsular plication.

Predictors of Poor Clinical Outcome After Arthroscopic Labral Preservation, Capsular Plication, and Cam Osteoplasty in the Setting of Borderline Hip Dysplasia

BACKGROUND

Borderline developmental dysplasia of the hip (BDDH) is frequently diagnosed concurrently with cam impingement. While hip arthroscopy has advanced the treatment of hip joint pathology, including femoroacetabular impingement (FAI), arthroscopic treatment for FAI in the setting of BDDH remains a challenge amid a subset of patients. The risk factors of poor clinical results after hip arthroscopic labral preservation and FAI corrections in the setting of BDDH patients have not been well established.

HYPOTHESIS

Pre- and intraoperative findings can predict the poor clinical outcomes after hip arthroscopic surgery for FAI in the setting of BDDH.

STUDY DESIGN

Case control study; Level of evidence, 3.

METHODS

Of patients with BDDH (defined as lateral center edge [LCE] angle between 20° and 25°) who underwent arthroscopic procedures for FAI between 2009 and 2014, 45 met inclusion criteria (45 hips: 15 males and 30 females). Their mean age was 31.4 years (range, 12-65 years), and the mean LCE angle was 23.2°. Clinical and radiographic follow-up evaluations up to a minimum of 2 years after surgery were performed for all patients. Failure of the procedure was defined as conversion to subsequent surgery or having a Tönnis osteoarthritis grade of 2, and success was defined as patients who did not need subsequent surgery. Univariate analysis and Cox hazard proportional analysis were performed for both cohorts.

RESULTS

Of 45 patients, 11 (24%) had revision surgery (endoscopic shelf acetabuloplasty for 5 patients, total hip arthroplasty for 2, and revision hip arthroscopy for 2) or advanced to Tönnis grade ≥2 osteoarthritis and thus constituted the failure group. In the success group, modified Harris Hip Score (median, pre- vs postoperative: 72.1 vs 100, P< .001, Wilcoxon signed-rank test) and nonarthritic hip score (58.8 vs 98.8, P< .001) were significantly improved at the minimum 2-year follow-up. The median age of the failure group was significantly higher than that of the success group (47.0 vs 20.0, P< .001, Mann-Whitney Utest). Risk factors of poor clinical outcomes were identified as follows: age ≥42 years (hazard ratio [HR], 11.6; 95% CI, 2.5-53.9; P= .002, Cox hazard model), broken Shenton line (HR, 6.4; 95% CI, 1.9-22.3; P= .003), Tönnis angle ≥15° (HR, 3.9; 95% CI, 1.2-12.9; P= .03), vertical center anterior (VCA) angle ≤17° (HR, 5.0; 95% CI, 1.5-17.1; P= .01), Tönnis grade 1 at preoperative radiograph (HR, 3.6; 95% CI, 1.1-11.7; P= .04), severe cartilage delamination at acetabulum (HR, 11.8; 95% CI, 3.0-46.1; P< .001), and mild cartilage damage at femoral head (HR, 8.1; 95% CI, 2.1-30.8; P= .002).

CONCLUSION

Preoperative predictors of poorer outcomes from hip arthroscopic labral preservation, capsular plication, and cam osteoplasty in the setting of BDDH are age ≥42 years old, broken Shenton line, osteoarthritis, Tönnis angle ≥15°, and VCA angle ≤17° on preoperative radiographs. Intraoperative predictors of poorer outcomes are severe acetabular chondral damage and even mild femoral chondral damage. Although the patients in the setting of BDDH may have good outcomes from isolated hip arthroscopy, caution is suggested for those with the aforementioned risk factors.

Prevalence of Femoral and Acetabular Version Abnormalities in Patients With Symptomatic Hip Disease: A Controlled Study of 538 Hips

BACKGROUND

Variations in femoral and acetabular version are becoming increasingly recognized as contributing factors to the development of hip pain in patients with femoroacetabular impingement (FAI) and hip dysplasia. It is still unknown what the true prevalence of these rotational abnormalities is in this patient population.

PURPOSE

To determine (1) the prevalence of femoral version abnormalities in symptomatic hips with FAI and hip dysplasia, (2) the prevalence of combined abnormalities of femoral and acetabular version in these patients, and (3) which specific hip morphologies are associated with abnormalities of femoral version.

STUDY DESIGN

Cross-sectional study; Level of evidence, 3.

METHODS

A total of 462 symptomatic patients (538 hips) were included who had hip pain attributed to FAI or hip dysplasia and who presented to our tertiary referral center for hip preservation surgery between 2011 and 2015. We retrospectively examined femoral and acetabular version among 11 subgroups with predefined hip morphologies and compared findings with a control group. The allocation to each subgroup was based on morphologic reference values for femoral head coverage, lateral center edge angle, alpha angle, and neck-shaft angle calculated on plain radiographs.

RESULTS

Of the 538 hips included, 52% were found to have abnormal femoral version; severe abnormalities were found in 17%. Severely decreased femoral version (<0°) was found in 5%; moderately decreased femoral version (0°-10°), in 17%; moderately increased femoral version (26°-35°), in 18%; and severely increased femoral version (>35°), in 12%. The most frequent abnormal combination was increased femoral version combined with normal acetabular version (22%). We found significantly lower mean femoral version for the cam-type FAI group (15°) and significantly higher mean femoral version for the Perthes hips (32°; ie, Legg-Calvé-Perthes disease) as compared with the control group (22°). The mean femoral version of the study group was 19°; for male patients, 15°; and for female patients, 22°.

CONCLUSION

Abnormalities in femoral version are highly prevalent in patients with hip pain who are eligible for hip preservation surgery, and severe abnormalities are prevalent in 1 of 6 patients (17%). Based on these results, the evaluation of young patients with hip pain should always include an assessment of femoral version and acetabular version to best decide what treatment approach should be undertaken to optimize outcomes.

Measurement of Femoral Version by MRI is as Reliable and Reproducible as CT in Children and Adolescents With Hip Disorders

BACKGROUND

Femoral version measurement techniques based on magnetic resonance imaging (MRI) studies have been developed as an alternative to the high levels of ionizing radiation associated with computed tomography (CT)-based methods. Previous studies have not evaluated the reliability, repeatability, and accuracy of MRI-based femoral version measurements in an adolescent population.

METHODS

Subjects who underwent MRI and CT studies for clinical suspicion of hip pain secondary to hip dysplasia or femoroacetabular impingement between 2011 and 2013 were identified. Rapid sequence femoral version images were obtained from MRI Hip dGEMRIC and/or postarthrogram studies. Femoral version images were also obtained from bilateral CT lower extremity, without contrast, studies. Measurements were made by 1 fellowship-trained, pediatric hip preservation attending surgeon, 2 pediatric orthopaedic surgical fellows, and 1 fellowship-trained musculoskeletal radiologist on 2 separate occasions. Linear mixed models were used to estimate the reliability and repeatability associated with CT-based and MRI-based measurements (intraclass correlation coefficients) and to estimate the agreement (CT-MRI) between the 2 techniques.

RESULTS

The mean age of 36 subjects was 15.4 years (±4.1 y). Interrater reliability was 0.91 (95% CI, 0.86-0.95) for the CT technique compared with 0.90 (95% CI, 0.86-0.94) for the rapid sequence MRI technique. Intrarater reliability for the CT technique was 0.96 (95% CI, 0.91-0.98) compared with 0.95 (95% CI, 0.90-0.97) for the MRI technique. The agreement between the MRI-based and CT-based techniques (bias: 1.9 degrees, limits of agreement: -11.3 to 14.9 degrees) was similar to the agreement between consecutive MRI measurements (bias: 0.4 degrees, limits of agreement: -7.8 to 8.6 degrees) as well as consecutive CT measurements (bias: 0.5 degrees, limits of agreement: -8.8 to 9.9 degrees).

CONCLUSIONS

The interrater and intrarater reliability and repeatability estimates (intraclass correlation coefficient values) associated with both techniques was excellent (>0.90). Acquirement of axial images at the pelvis and knee during MRI for investigation of adolescents with hip pain allows for reliable measurement of femoral version.

LEVEL OF EVIDENCE

Level II-diagnostic study.

Comprehensive Clinical Evaluation of Femoroacetabular Impingement: Part 3, Magnetic Resonance Imaging

Radiologic imaging is an essential supplement to the physical examination in the evaluation of a patient with femoroacetabular impingement. Plain radiographs are the initial modality of choice for the evaluation of bony anatomy and pathology. Magnetic resonance imaging supplements the physical examination and standard radiographs by enabling qualitative and quantitative evaluation of both articular cartilage and soft tissues about the hip. Magnetic resonance imaging also provides improved 3-dimensional characterization of the bony anatomy owing to the multiplanar nature of this technique. This article describes a comprehensive approach to interpretation of magnetic resonance examination of the hip.

Bony Morphology of Femoroacetabular Impingement in Young Female Dancers and Single-Sport Athletes

BACKGROUND

Femoroacetabular impingement (FAI) is a painful and limiting condition of the hip that is often seen in young athletes. Previous studies have reported a higher prevalence of this disorder in male athletes, but data on the structural morphology of adolescent and young adult female athletes, specifically those involved in dance, are lacking.

PURPOSE

(1) To investigate the radiographic morphology of FAI deformities in adolescent and young adult female single-sport dance and nondance athletes and (2) to examine the differences in the radiographic findings between these 2 groups.

STUDY DESIGN

Cross-sectional study; Level of evidence, 3.

METHODS

A retrospective chart review of 56 female single-sport athletes 10 to 21 years of age with a diagnosis of FAI within a single-sports medicine division of a pediatric academic medical center was performed. Acetabular index (AI), lateral center-edge angle (LCEA), crossover sign, and ischial spine sign were measured bilaterally on anteroposterior radiographs; alpha angle (AA) was measured on lateral films, and anterior center-edge angle (ACEA) was measured on false-profile films. Independent t tests and Mann-Whitney U tests were used to compare mean angle measurements between dance and nondance athletes. Dichotomized categorical variables and crossover and ischial spine signs were analyzed between dance and nondance athletes by applying a chi-square test. Statistical significance was set as P < .05 a priori.

RESULTS

Significant differences in angle measurements were noted. AA was significantly lower in the dancers compared with the nondance athlete group (49.5° ± 6.0° vs 53.9° ± 7.3°, P = .001). The LCEA and ACEA of dance athletes were significantly greater compared with nondance athletes (33.8° ± 6.7° vs 30.9° ± 5.8° [P = .016] and 36.0° ± 8.1° vs 32.3° ± 7.0° [P = .035], respectively). No significant difference in AI was seen between the 2 cohorts (5.0° ± 4.0° for dancers vs 5.9° ± 3.4° for nondancers, P = .195).

CONCLUSION

Significant differences existed in the radiographic bony morphology of young female single-sport dance athletes compared with nondance athletes with FAI. In dance athletes, symptoms were seen in the setting of normal bony morphology.

Proximal femoral derotation osteotomy for idiopathic excessive femoral anteversion and intoeing gait

Aim: The purpose of this study is to assess the symptoms caused by excessive femoral anteversion and the outcomes of femoral derotation osteotomy.

Methods: We reviewed data on patients who underwent proximal femoral derotation osteotomy for symptomatic intoeing gait caused by femoral anteversion. Only symptomatic patients were considered for corrective derotation osteotomy. Degree of femoral anteversion was confirmed on computed tomography (CT) scan.

Results: Thirty-five extremities were operated in 21 patients with an average age of 13.3 (8–18) years. Mean follow-up was 16 months (6–36 months). Mean femoral anteversion angle was 40.8° (28°–53°). External rotation of extended hips improved significantly, from 30° to 51.8° (p < 0.0001). Mean foot progressing angle improved from 15.2° internally rotated preoperatively to 7.7° externally rotated. Intoeing completely resolved in all except two patients. Thirteen out of 21 children complained about tripping and frequent falling while running and playing sports, eight patients had hip pain while 13 children had knee pain preoperatively. Tripping, falling and hip pain resolved in all patients postoperatively, while three patients whose primary complaint was knee pain failed to improve postsurgery. Eighteen of the 21 parents were satisfied with the decision to perform surgical correction.

Conclusion: Excessive femoral anteversion can present with unexplained hip or knee pain refractory to conservative treatments. Careful assessment of lower limb malalignment is a valuable tool in such circumstances and derotation proximal femoral osteotomy can certainly be a procedure of choice in carefully selected cases.

Abnormal femoral antetorsion-a subtrochanteric deformity

Femoral rotational malalignment is associated with pain and functional disability and may be a contributing factor to hip impingement as well as to instability. In general, the deformity can be addressed surgically by rotational osteotomy. However, the anatomic location of the deformity is debated. The goal of the present study was to narrow down the anatomic site of deformity using the lesser trochanter (LT) as an additional landmark. One hundred and eight patients underwent computer tomography (CT)-based rotational analysis of their lower extremities. Femoral torsion (FT) and LT torsion (LTT) were measured. The combined angle (CoA) between FT and LTT was calculated. Statistical evaluation was done by multiple regression analysis. Ninety-seven extremities were examined for FT and LTT. Average age was 41 years (SD = 16.9) with a range of 18–85 years. Mean values were 20° for FT (SD = 12.2) and −16° for LTT (SD = 11.3). Mean CoA was 37.2 (SD = 8.7). Statistical analysis reveals a strong linear relationship between FT and LTT (y=31+0.74x) and a weaker relationship between FT and CoA (y=31+0.24x). This study identifies the LT as a reliable landmark and shows a strong linear relationship between the orientation of the LT and the overall torsion of the femur below and above the LT with about two-thirds of torsional changes occurring distal to it. These results provide a considerable indication for a subtrochanteric osteotomy to address correction of femoral rotational deformity at its anatomical origin.

Level of Evidence: Level III, observational study.

Comparison of Intraoperative Fluoroscopic Dunn View With Magnetic Resonance Imaging to Determine Femoral Version

PURPOSE

To compare femoral version measured with a fluoroscopic Dunn view taken at the time of hip arthroscopy with values derived from axial magnetic resonance imaging (MRI) scans.

METHODS

Of 159 hip arthroscopies performed from January 2014 through March 2015, 50 patients had magnetic resonance imaging (MRI) scans with a protocol that incorporates femoral version analysis. Dunn views are performed as a routine part of the preoperative fluoroscopic examination at the time of arthroscopy. Femoral version was measured from the fluoroscopic views and compared with values calculated from axial MRI images. The measurements were compared with a paired t test for difference in means, the intraclass correlation coefficient (ICC) for reliability, and the limits of agreement method of Bland and Altman.

RESULTS

There was a very small but statistically significant difference between the measurement on fluoroscopic Dunn view and the value on axial MRI (mean difference, 1.4°, P = .03). The ICC was 0.809 (P < .0001), indicating substantial agreement. By the Bland and Altman method, the 95% limits of agreement for fluoroscopic versus MRI measurement were -7.6 to 10.4, with no significant difference in variance by Pitman test (P = .526).

CONCLUSIONS

With careful attention to technique, the fluoroscopically simulated Dunn view can be used to measure femoral version with acceptable accuracy and obviates the need for repeat 3-dimensional imaging for patients who already have an MRI scan without version analysis.

LEVEL OF EVIDENCE

Level II, testing of previously developed diagnostic criteria with a gold standard.